RESPONSE OF DAIRY-CATTLE TO TRANSIENT VOLTAGES AND MAGNETIC-FIELDS

Stray voltages in dairy facilities have been studied since the 1970's. Previous research using steady-state ac and de voltages has defined c ow-contact voltage levels which may cause behavioral and associated pr oduction problems. This research was designed to address concerns over possible effects of transient voltages and magnetic fields on dairy c ows. Dairy cow response to transient voltages and magnetic fields was measured. The waveforms of the transient voltages applied were: 5 cycl es of 60-Hz ac with a total pulse time of 83 ms, 1 cycle of 60-Hz ac w ith a total pulse time of 16 ms, and 1 cycle of an ac square wave (spi king positive and negative) of 2-ms duration. Alternating magnetic fie lds were produced by passing 60-Hz ac fundamental frequency with 2nd a nd 3rd harmonic and random noise components in metal structures around the cows. The maximum magnetic held associated with this current how was in excess of 4 G. A wide range of sensitivity to transient voltage s was observed among cows. Response levels from 24 cows to each transi ent exposure were normally distributed. No responses to magnetic field s were observed.